MutL associates with Escherichia coli RecA and inhibits its ATPase activity

Different DNA repair systems are known to cooperate to deal with DNA damage. However, the regulatory role of the cross-talk between these pathways is unclear. Here, we have shown that MutL, an essential component of mismatch repair, is a RecA-interacting protein, and that its highly conserved N-terminal domain is sufficient for this interaction. Surface plasmon resonance and capillary electrophoresis analyses revealed that MutL has little effect on RecA–ssDNA filament formation, but dose down-regulate the ATPase activity of RecA. Our findings identify a new role for MutL, and suggest its regulatory role in homologous recombination.